An interconnection substrate may have a barcode, which is scanned for the purpose of managing the process of manufacturing interconnection substrates. The surface metal layer of a core layer that includes a resin layer and the metal layer disposed thereon may be gouged by laser, for example, to form a hole in the metal layer or to form a hole into the resin layer through the metal layer, thereby producing a rectangular cell. A plurality of rectangular cells in contact with one another are then arranged in a matrix form to form a two-dimensional barcode (see Patent Document 1, for example).
However, a conventional barcode formed by engraving the surface of an interconnection substrate as described above is not viewable after an insulating layer made of resin and/or an interconnection layer made of metal are formed on the barcode. In such a state, a conventional optical barcode reader that scans barcode cells and the background by detecting color tones or surface unevenness is unable to perform a scan.
Accordingly, it may be preferable to provide an interconnection substrate having a barcode that is readable even after an insulating layer and/or an interconnection layer are laminated on the barcode.
[Patent Document 1] Japanese Patent Application Publication No. 2006-259204